Torque drive unit

Abstract

A drive assembly is provided including first and second torque input and torque output sections coupled together for relative rotation and limited relative displacement along the axis of relative rotation thereof. The input section includes structure for applying rotational torque thereto and the output section includes structure for applying rotary torque to a rotary driven member. Spring structure is connected between the sections yieldingly biasing the latter toward one set of limit positions of displacement along said axis and one of the units includes a spiral ramp concentric with the axis of relative rotation and the other of the sections includes a follower engaged with the ramp. The spiral ramp terminates at one end thereof in a circumferential race concentric with the axis of relative rotation of the sections and in which the follower is guidingly receivable for continuous movement therethrough after movement along the ramp from the end thereof remote from the race into the latter. The sections are displaced along the axis of relative rotation against the biasing action of the spring during movement of the follower along the ramp toward the race.

What is claimed as new is as follows: 
     
       1. A torque overload release drive unit including first and second torque input and torque output sections, said sections including coacting means coupling said sections together for relative rotation, and limited relative displacement along the axis of relative rotation of said sections, said input section including means for applying rotational torque thereto and said output section including means for applying rotary torque to a rotary driven member, spring means connected between said sections yieldingly biasing said sections toward one set of limit positions of displacement along said axis, one of said units including spiral ramp means concentric with said axis and the other of said sections including follower means engaged with said ramp means, said spiral ramp means terminating at one end thereof in a circumferential race means onto which said ramp means opens and in which the follower means is guidingly receivable for continuous movement therethrough after movement along said ramp means from the end thereof remote from said race means into the latter, said sections being displaced along said axis against the biasing action of said spring means during movement of said follower means along said ramp means toward said race means. 
     
     
       2. The combination of claim 1 wherein said spring means and one of said sections include coacting means operative to variably adjust said spring means and thus the biasing action exerted thereby. 
     
     
       3. The combination of claim 1 wherein said ramp comprises a spiral groove formed in said one section and a follower projecting outwardly from the other section generally radially of said axis and guidingly received in said groove. 
     
     
       4. The combination of claim 3 wherein said spring means and one of said sections include coacting means operative to variably adjust said spring means and thus the biasing action exerted thereby. 
     
     
       5. The combination of claim 1 wherein said one unit includes a pivoted ramp for closing the end of said ramp means opening into said race, said pivoted ramp being swingable between a first position projecting into said race and opening the end of the ramp means into said race and a second position bridging the last mentioned ramp means end. 
     
     
       6. The combination of claim 1 wherein said follower means includes at least one pin stationarily supported from said other section and projecting outwardly therefrom generally radially of said axis. 
     
     
       7. The combination of claim 1 wherein said follower means includes at least one pair of side-by-side pins supported from said other section and projecting outwardly therefrom generally radially of said axis, said pins being supported from said other section for shifting between first positions spaced along a spiral path concentric with said axis and of an incline corresponding to the incline of said spiral ramp means and second positions spaced along a circle concentric with said axis. 
     
     
       8. The combination of claim 1 wherein said one unit includes a pivoted ramp for closing the end of said ramp means opening into said race, said pivoted ramp being swingable between a first position projecting into said race and opening the end of the ramp means into said race and a second position bridging the last mentioned ramp means end, said follower means including at least one pin stationarily supported from said other section and projecting outwardly therefrom generally radially of said axis. 
     
     
       9. The combination of claim 1 wherein said sections include shaft portions concentric with said axis and having remote ends facing in opposite directions along said axis, said shaft portions comprising said means for applying rotational torque to said input section and for applying rotary torque to a rotary driven member.